Method and system for creating and deploying a mesh network

ABSTRACT

A method and system for creating and deploying a mesh network are disclosed. In one embodiment, the method comprises providing a mesh router having a plurality of radios. The mesh router is used in a cell of a plurality of cells that covers a geographic region. Channels are assigned to the plurality of radios. The channels are selected from a plurality of channels to allow channel reuse throughout the plurality of cells.

The present application is a continuation of U.S. patent applicationSer. No. 12/169,215, entitled “Method and System for Creating andDeploying a Mesh Network” and filed on Jul. 8, 2008, which is acontinuation of U.S. Pat. No. 7,415,278, entitled “Method and System forCreating and Deploying a Mesh Network” and filed on Aug. 10, 2005, whichclaims the benefit of and priority to U.S. Provisional PatentApplication No. 60/622,223, entitled “Cellular Mesh Architecture” andfiled on Oct. 24, 2004. Priority to these prior patent and patentapplications is expressly claimed. The disclosures of aforementionedpatent and patent applications are hereby incorporated by reference intheir entirety.

FIELD OF THE INVENTION

The field of the invention relates generally to wireless networks andmore particularly relates to a method and system for creating anddeploying a mesh network.

BACKGROUND

High speed and high performance network access are needed in many areaswhere wired infrastructure is non-existent, outdated, or impractical.Fixed wireless broadband networks can fulfill this need. However, use ofexisting fixed wireless broadband technology is limited due to acombination of technological constraints and high deployment costs. Forexample, Wireless Local Area Network (WLAN) technology requires multipleaccess points where each access point must be connected via cable to awired backbone infrastructure. As a result, the network becomesdifficult and costly to deploy.

To address these problems, wireless mesh network architecture has beenstudied as a system for becoming part of the network infrastructure andproviding wireless access to users. However, wireless mesh networking islimited by its network capacity due to the requirement that nodesforward each other's packets. For example, a uniform random network withrandom traffic pattern has an end-to-end throughput of 1/n^(1/2),wherein is the total number of nodes. Therefore, throughput approacheszero as the number of nodes increase.

There are two fundamental reasons that result in diminished throughput.First, current 802.11 Media Access Control (MAC) protocol is inefficientand unfair in multi-hop environments. For example, 802.11 radios cannottransmit and receive at the same time; 802.11 MAC protocol does notcorrectly solve hidden terminal problems in a mesh; and Request to Send(RTS)/Clear to Send (CTS) scheduling along a multi-hop chain can causeTransmission Control Protocol (TCP) fairness problems and back-offinefficiencies. Second, only a small portion of the available spectrumis used. For example, 802.11b/g has three non-overlapping channels and802.11a has twelve non-overlapping channels, but 802.11 is designed touse only a single channel frequency at any given time.

In the past, one possible solution was to improve the 802.11 MAC layer.However, this would require changes to the MAC and hardware, which wouldbe expensive and take a significant amount of time to complete.

Alternatively, network capacity can be increased by using multipleradios and multiple channels. For example, a link layer protocol calledthe Multi-radio Unification Protocol (MUP) has been proposed tocoordinate the operation of multiple wireless network cards tuned tonon-overlapping frequency channels. However, there is inefficient use ofavailable frequencies because all the nodes in the network use the samefixed channels to talk to their neighbors. As a result, no frequencyreuse is available. Furthermore, same-radio packet relay, or theinability to transmit and receive packets at the same time, cannot becompletely avoided.

SUMMARY

A method and system for creating and deploying a mesh network aredisclosed. In one embodiment, the method comprises providing a meshrouter having a plurality of radios. The mesh router is used in a cellof a plurality of cells that covers a geographic region. Channels areassigned to the plurality of radios. The channels are selected from aplurality of channels to allow channel reuse throughout the plurality ofcells.

The above and other preferred features, including various novel detailsof implementation and combination of elements, will now be moreparticularly described with reference to the accompanying drawings andpointed out in the claims. It will be understood that the particularmethods and systems described herein are shown by way of illustrationonly and not as limitations. As will be understood by those skilled inthe art, the principles and features described herein may be employed invarious and numerous embodiments without departing from the scope of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included as part of the presentspecification, illustrate the presently preferred embodiment of thepresent invention and together with the general description given aboveand the detailed description of the preferred embodiment given belowserve to explain and teach the principles of the present invention.

FIG. 1 illustrates a block diagram of a prior art network;

FIG. 2 illustrates a block diagram of an exemplary wireless meshnetwork, according to one embodiment of the present invention;

FIG. 3 illustrates a block diagram of multiple hexagonal cells of a meshnetwork, according to one embodiment of the present invention;

FIG. 4 illustrates a block diagram of a mesh network having multiplehexagonal cells that include channel assignments for mesh routers,according to one embodiment of the present invention.

FIG. 5 illustrates a block diagram of an exemplary wireless card,according to one embodiment of the present invention;

FIG. 6 illustrates a block diagram of an exemplary wireless local areanetwork router used to communicate with a mesh router, according to oneembodiment of the present invention;

FIG. 7 illustrates a block diagram of an exemplary mesh router,according to one embodiment of the present invention;

FIG. 8 illustrates a flow diagram of an exemplary process for assigningchannels in a mesh network, according to one embodiment of the presentinvention;

FIG. 9 illustrates a flow diagram of an exemplary network packet flowprocess, according to one embodiment of the present invention.

DETAILED DESCRIPTION

A method and system for creating and deploying a mesh network aredisclosed. In one embodiment, the method comprises providing a meshrouter having a plurality of radios. The mesh router is used in a cellof a plurality of cells that covers a geographic region. Channels areassigned to the plurality of radios. The channels are selected from aplurality of channels to allow channel reuse throughout the plurality ofcells.

In the following description, for purposes of explanation, specificnomenclature is set forth to provide a thorough understanding of thevarious inventive concepts disclosed herein. However, it will beapparent to one skilled in the art that these specific details are notrequired in order to practice the various inventive concepts disclosedherein.

Some portions of the detailed descriptions that follow are presented interms of wireless networks and computer systems. These wireless networkdescriptions and representations are the means used by those skilled inthe wireless networking arts to most effectively convey the substance oftheir work to others skilled in the art. A wireless network is here, andgenerally, conceived to be a system for communications among two or morecomputers using radio waves as its carrier. Usually, though notnecessarily, the information communicated between computer systems takesthe form of packets. Furthermore, for reasons of common usage, thecomponents of the packets are referred to as bits, values, elements,symbols, characters, terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. Unlessspecifically stated otherwise as apparent from the following discussion,it is appreciated that throughout the description, discussions utilizingterms such as “router” or “radio” or “frequency” or “channel” or“backbone” or “packet” or “communicate” or the like, refer to thecomponents, and actions and processes of a network, or similarcommunication system, that transfers data represented as physical(electronic) quantities within the computer system's registers andmemories or other such information storage, transmission or displaydevice from one computer system to another.

The present invention also relates to apparatus for performing theoperations herein. This apparatus may be specially constructed for therequired purposes, or it may comprise a general-purpose computerselectively activated or reconfigured by a computer program stored inthe computer. Such a computer program may be stored in a computerreadable storage medium, such as, but is not limited to, any type ofdisk including floppy disks, optical disks, CD-ROMs, andmagnetic-optical disks, read-only memories, random access memories,EPROMs, EEPROMs, magnetic or optical cards, or any type of mediasuitable for storing electronic instructions, and each coupled to acomputer system bus.

The methods presented herein are not inherently related to anyparticular computer or other apparatus. Various general-purpose systemsmay be used with programs in accordance with the teachings herein, or itmay prove convenient to construct more specialized apparatus to performthe required method steps. The required structure for a variety of thesesystems will appear from the description below. In addition, the presentinvention is not described with reference to any particular programminglanguage. It will be appreciated that a variety of programming languagesmay be used to implement the teachings of the invention as describedherein.

FIG. 1 illustrates a block diagram of a prior art network 199. In FIG.1, the Internet 100 is connected to a variety of networks, any of whichmay be wireless networks. For example wireless networks may cover aneighborhood 110, office buildings 120, government areas 130, and/oruniversities and colleges 140. The Internet 100 may be a system ofinterconnected computer networks, local area networks, wide areanetworks, virtual private networks, or other networks that areconfigured to transmit data by packet switching using standardizedprotocols, such as Internet Protocol. Interconnected computer networksfacilitate the transfer of information and services, which may includeelectronic mail, file sharing, and access to the World Wide Web. Thevarious networks 110-140 may have any of a variety of wirelessarchitectures—for example: a wireless local area network, wirelessmetropolitan area network, wireless wide area network, or other similarwireless network.

FIG. 2 illustrates a block diagram of an exemplary wireless meshnetwork, according to one embodiment of the present invention. Meshnetwork 200 may be part of a wireless network, such as neighborhood 212.According to one embodiment, the neighborhood 212 is divided into anumber of hexagonal cells 210, where each individual cell 211 includesone or more subscribers 220 to the wireless mesh network 200. Thedivision of the neighborhood 212 is a logical division, and the physicalboundaries between cells in network 200 are only representations of thelogical network operation. A hexagonal cell 211 may or may not encompassa subscriber 220 because a particular cell may be situated such that nosubscribers happen to be located within its area.

According to one embodiment, a subscriber 220 is a computer systemauthorized to access the neighborhood 212 wireless network 200. Asubscriber 220 may be situated in a neighborhood home, in a car, oranywhere within the network coverage area. In addition to the meshnetwork, it is to be appreciated that other systems employing thevarious teachings herein may also be used to practice the variousaspects of the present invention, and as such, are considered to bewithin its full scope.

FIG. 3 illustrates a block diagram of multiple hexagonal cells 399 of amesh network, according to one embodiment of the present invention.Hexagonal cells 399 are a logical network representation and are notmeant to define actual physical boundaries. Each cell 211 of thehexagonal cells 399 includes a mesh router 300. A mesh router 300communicates with exemplary subscribers 330-350. A mesh router 300 mayhave three backbone radios 310 and one access radio 320. The threebackbone radios 310 are used to communicate with other mesh routers. Theaccess radio may be used to communicate with multiple subscribers330-350. The three backbone radios 310 are assigned three separatechannels and the access radio 320 is also assigned a separate channel.One exemplary method of assignment is to use 802.11b/g radios for localaccess and 802.11a radios for the mesh backhaul. Although a mesh router300 having three backbone radios 310 and a local access radio 320 havebeen described, the use of other mesh router configurations is withinthe scope of the present invention.

A mesh router 300 communicates with subscribers 330-350 through theaccess radio 320. The subscribers 330-350 need to be setup withsubscriber accounts in order to gain access to the mesh network, such asmesh network 200, through a mesh router 300. These subscribers mayinclude a wireless personal digital assistant (PDA) 340, a wirelesslocal area network (LAN) router 350, or a wireless laptop 330. Awireless PDA 340 may include Palm Pilots with wireless capabilities,Blackberrys, or other hand-held device with wireless capabilities. Awireless LAN router 350 may include any network routers that cancommunicate with a mesh router 300. A wireless laptop 330 may includeany computer system with wireless capabilities. Although a wireless PDA340, a wireless LAN router 350, and a wireless laptop 330 are described,any device with wireless capability may be considered as subscribers.

Mesh routers 300 may also serve as gateways 390 to the Internet 100.According to one embodiment, mesh router/gateway 390 has at least onenetwork interface, such as an ethernet controller that a connection tothe Internet 100 via a communications link 370, such as Ethernet. In amesh network, multiple gateways 390 may exist. Gateway 390 allows meshrouters 300 to access the Internet.

The mesh network topology of FIG. 3 may also include a networkmanagement server 360. Network management server 360 may be connected toa gateway 390 through the Internet 100. According to one embodiment, thenetwork management server 360 designates the channel assignments of allmesh routers 300 in the mesh network.

FIG. 4 illustrates a block diagram of a mesh network 499 having multiplehexagonal cells that include channel assignments for mesh routers400-407, according to one embodiment of the present invention. Each ofthe mesh routers 400-407 are assigned three different channels accordingto the exemplary process described in FIG. 8. Each of the mesh routers400-407 has three backbone radios 310 which utilize sevennon-overlapping frequencies or channels, channels 1-7, throughout theentire mesh network 499, These seven non-overlapping channels providedirect links between all neighboring cells.

For example, cell 411 has six neighbors 412-417. Cell 411 has threebackhaul channels (3, 4, 5) used to communicate with the six neighbors412-417. The channels are assigned to the mesh routers 401-407 such thattwo neighboring mesh routers have one backhaul radio channel in common.For example neighboring mesh routers 402, 403 have backhaul channel 3 incommon with mesh router 401. Channel 3 is the only channel that meshrouters 401-403 have in common. Similarly, channel 4 is the only channelthat mesh router 401 has in common with mesh routers 404, 405. Andchannel 5 is the only channel that mesh router 401 has in common withmesh routers 406, 407.

Each channel is reused in nearby, but not adjacent cells. For eachchannel, there is a buffer about two cells wide where a channel is notbeing reused allowing for good separation and low co-channelinterference. For example, channel 3 used by mesh routers 401-403 is notused by any mesh routers in neighboring cells 414-422. In other words,it would take two hops before channel 3 is reused. By systematicallyspacing mesh routers 400 and their channel groups, the availablechannels are distributed throughout the geographic region 499 and may bereused as many times as necessary so long as the interference betweenco-channel mesh routers is kept below acceptable levels.

In addition, because mesh routers 400 use three different channels, themesh backhaul network 499 avoids same-radio packet relay. Because themesh backhaul network 499 avoids same-radio packet relay, end-to-endthroughput does not decrease as the number of mesh routers 400increases. This allows for the architecture to scale.

According to one embodiment, efficient scaling is supported byconfiguring each mesh router with three backhaul radios on threedifferent channels, as described above. Assuming that 802.11a radios areused, the throughput of each backhaul radio is up to 54 Mbps. As threeneighboring backhaul radios on the same channel consist of a backhaulWLAN and share the bandwidth, the throughput of each backhaul radio isroughly ⅓ of 54 Mbps. As all the same-radio packet relay is completelyavoided, the throughput of the relay nodes is not halved and all thetraffic, no matter local or remote, will not change the end-to-endthroughput available to each mesh router.

For example, the end-to-end backhaul throughput T available to each meshrouter is:T=54 Mbps*(⅓)*3=54 Mbps  (1)Note that in (1), the end-to-end throughput T available to each meshrouter is a constant, and is not related to n, the number of nodes inthe network. In another word, the end-to-end throughput available toeach node is O (1), which simply means that this architecture scales. Itshould be noted that although IEEE 802.11 based radios are oftenassumed, the present embodiments of the invention are by no meanslimited to using 802.11 radios. It is entirely possible that, if foundbeneficial, other radio technologies can also be used which are highlyflexible and radio-agnostic.

The mesh network 499 does not share spectrum for access and backhaul,further improving capacity. If IEEE 802.11 based technology is used, themesh router 400 could use 802.11b/g radios for local access (e.g., radio320) and 802.11a radios for mesh backhaul network (e.g., radios 310).

FIG. 5 illustrates a block diagram of an exemplary wireless card 500 foruse in a mesh network, according to one embodiment of the presentinvention. Wireless card 500 may be used with a laptop or desktopcomputer. According to one embodiment, the wireless network card 500 hasa peripheral component interconnect (PCI) interface 520 that connectsthe network card 500 to the computer. The wireless network card 500 alsohas a processor 510 connected to a random access memory (RAM) module 530and 802.11 controller 540. The 802.11 controller 540 allows the networkcard's processor 510 to communicate with the 802.11 antennae 550.

FIG. 6 illustrates a block diagram of an exemplary wireless router 600,according to one embodiment of the present invention. In FIG. 6, awireless local area network router 600 allows subscribers to set uptheir own local area networks. Wireless local area network router 600may be a Wi-Fi router such as router 350. The wireless local areanetwork router 600 has a processor 610 connected to the power supply620, random access memory (RAM) module 630, a Ethernet controller 640,and a 802.11 controller 650. The Ethernet controller 640 allows theprocessor 610 to communicate with Ethernet adapter 660. The 802.11controller 650 allows the processor 610 to communicate with the 802.11antennae 670.

FIG. 7 illustrates a block diagram of an exemplary wireless mesh router700, according to one embodiment of the present invention. In FIG. 7,the mesh router 700 has a processor 710 connected to the power supply720, random access memory (RAM) module 730, and radio controllers 740.Mesh router 700 may be a mesh router, such as mesh router 300. The radiocontrollers 740 may include three backhaul radio controllers 740 a, 740b, 740 c, and one local access radio controller, 740 d. Each backhaulradio controller 740 a, 740 b, 740 c allows the processor 710 tocommunicate with the backhaul radio antennae 750 a, 750 b, 750 c. Themesh router 700 uses 120 o sectored directional antennas in order toreduce co-channel interference, according to one embodiment of thepresent invention. The local access radio controller 740 d allows theprocessor 710 to communicate with the local access radio antenna 750 d.Although three radio controllers are described, the mesh router 300 mayinclude more or fewer controllers based on available router technologyand the network topology.

According to one embodiment, a mesh router 700 may also include at leastone communications interface 770, such as an Ethernet interface, thatenables communication with the Internet and act as a gateway 390 forother mesh routers in the network. An interface controller 760 allowsthe processor 710 to communicate with the interface 770. In alternateembodiments, the communications interface 770 is a wirelesscommunications interface. In addition, components of mesh router 700 maybe integrated with each other.

FIG. 8 illustrates a flow diagram of an exemplary process 800 fordeploying a mesh network, according to one embodiment of the presentinvention. In FIG. 8, a network provider may set up a mesh network byfirst dividing the geographic region for network deployment into cells210, where the cells may be hexagonal. (802) This division is a logicalnetwork representation and is not meant to define actual physicalboundaries. At least one mesh router 300 is installed in each hexagonalcell. (804) When a mesh router 700 is first powered up (e.g., before anychannels are assigned to it), the mesh router 700 first tries to findneighboring routers using its backhaul radios 750 a, 750 b, 750 c on adefault channel. (806)

If any neighboring routers which have a gateway is found (808), the meshrouter 700 will send a channel assignment request and its ownconfiguration information to the network management server 360 throughthat neighbor. (810) The network management server 360 is connected tothe gateway 390 and in charge of the channel assignment of the wholenetwork (e.g., mesh network 499). Upon receiving the channel assignmentrequest from the mesh router 700, the network management server 360 usesa simple set of rules and the network topology information stored in itsdatabase to decide which channels to assign to that mesh router 700. Thenetwork management server 360 then sends the channel assignments to themesh router 700. (812)

If after a certain timeout period, no neighbors that have a gateway tothe network management server 360 can be found using the defaultchannel, the mesh router 700 will automatically start to scan thechannels in an attempt to find neighbors that have a gateway 390, andwill continue trying until successful. (814) This can happen duringincremental deployment. Incremental deployment typically involvessituations where a new mesh router is added to a mesh network comprisedof mesh routers whose channels have already been assigned by the networkmanagement server 360. In this case, it is possible that none of the newmesh router's neighbors uses the default channel. As a result, the newmesh router 700 needs to scan the channels in order to communicate withits neighbors and to find one that has a gateway to the networkmanagement server 360.

FIG. 9 illustrates an exemplary process 900 of how a packet is sentthrough a mesh network, according to one embodiment of the presentinvention. In FIG. 9, a packet is sent by a subscriber 220 located in acell that includes a mesh router, for example mesh router 401. (902) Themesh router 401 receives the packet and decides if the packet isdestined for a subscriber within its boundary 411. (904) If so, then thepacket is sent to the destination computer or system. (910) If not, thenthe packet is sent to the next appropriate mesh router in a neighboringcell 412 according to a predetermined routing table. (906) The next meshrouter 402 receives the packet and follows the same decision process asthe previous mesh router 401. (904)

The present embodiments of a mesh network architecture address many ofthe problems encountered in deploying prior art wireless mesh network.Some of the benefits of the present mesh network architecture include,but are not limited to, scalability, capacity, cost effectiveness,flexibility, simplicity, and robustness. The present mesh networkarchitecture provides scalability by using multiple radios, utilizingcell-based wide area broadband coverage, and keeping the end-to-endbackhaul throughput available to each mesh router at a constant level,i.e., throughput does not decrease as the number of nodes increases.This network capacity is at least an order of magnitude greater than thecapacity of prior art mesh networks and is accomplished withoutrequiring any changes to standard 802.11 MAC and hardware. In addition,cost is reduced by minimizing the number of backhaul radios required todeploy a mesh network. In additional embodiments, to further reducecost, a more compact, simpler mesh router with one access radio and onebackhaul radio could be used as an edge node or to terminate the mesh.

A method and system for creating and deploying a mesh network have beendisclosed. Although the present methods and systems have been describedwith respect to specific examples and subsystems, it will be apparent tothose of ordinary skill in the art that it is not limited to thesespecific examples or subsystems but extends to other embodiments aswell.

1. A method comprising: communicating, at a network device in a cell ofa mesh network, to at least three neighboring cells in the mesh networkthrough at least three backhaul radio antennas respectively, eachbackhaul radio antenna of the at least three backhaul radio antennascomprises a sectored directional antenna corresponding to a respectivedirection; assigning a separate channel associated with a first backhaulradio antenna in the cell, wherein other backhaul radio antennas of theat least three backhaul radio antennas in the cell are assigned to adifferent channel from the separate channel; and reassigning theseparate channel in another cell that is (1) approximately opposite tothe direction corresponding to the sectored directional antenna, and (2)adjacent to one of the at least three neighboring cells.
 2. The methodof claim 1, further comprising: communicating, at the network device, toa plurality of network subscribers through an access radio antenna,wherein the access radio antenna is assigned a separate channel.
 3. Themethod of claim 1, wherein each backhaul radio antenna comprises atri-sectored directional antenna.
 4. The method of claim 2, wherein theseparate channel assigned to the access radio antenna is in a differentcommunication band from the separate channels assigned to the at leastthree backhaul radio antennas.
 5. A method comprising: dividing, by anetwork management server, a mesh network into a plurality of logicalcells; placing a mesh router in each logical cell; receiving a channelassignment request from a respective mesh router responsive to the meshrouter finding another neighboring mesh router that has a gateway to thenetwork management server; determining a channel assignment for therespective mesh router based on a set of predetermined rules and networktopology in response to the received channel assignment request; andsending the channel assignment to the respective mesh router.
 6. Themethod of claim 5, wherein the set of predetermined rules comprises:assigning a first channel associated with a first backhaul radio antennaof the respective mesh router in a logical cell, a second channelassociated with a second backhaul radio antenna and a third channelassociated with a third backhaul radio antenna where each of the firstchannel, second channel and the third channel are different from oneanother; and reassigning the first channel in another logical cell thatis (1) approximately opposite to the direction corresponding to asectored directional antenna of the first backhaul radio antenna, and(2) non-adjacent to the logical cell.
 7. The method of claim 5, whereinthe mesh router finds another neighboring mesh router that has a gatewayto the network management server through a default channel.
 8. Themethod of claim 5, wherein, responsive to the mesh router not findinganother neighboring mesh router that has a gateway to the networkmanagement server through a default channel, the mesh router scanschannels to find the other neighboring mesh router that has the gatewayto the network management server.
 9. The method of claim 5, wherein themesh router is placed during an incremental deployment.
 10. A networkdevice in a cell of a mesh network, the network device comprising: aprocessor; a memory; a communicating mechanism coupled to the processor,the communicating mechanism to communicate to at least three neighboringcells in the mesh network through at least three backhaul radio antennasrespectively, each backhaul radio antenna of the at least three backhaulradio antennas comprises a sectored directional antenna corresponding toa respective direction; an assigning mechanism coupled to the processor,the assigning mechanism to assign a separate channel associated with arespective backhaul radio antenna in the cell, wherein other backhaulradio antennas in the cell are assigned to a different channel from theseparate channel; and wherein the assigning mechanism further reassignsthe separate channel in another cell that is (1) approximately oppositeto the direction corresponding to the sectored directional antenna, and(2) adjacent to one of the at least three neighboring cells.
 11. Thenetwork device of claim 10, wherein the communicating mechanism furtherto: communicate to a plurality of network subscribers through an accessradio antenna, wherein the access radio antenna is assigned a separatechannel.
 12. The network device of claim 10, wherein each backhaul radioantenna comprises a tri-sectored directional antenna.
 13. The networkdevice of claim 11, wherein the separate channel assigned to the accessradio antenna is in a different communication band from the separatechannels assigned to the at least three backhaul radio antennas.
 14. Anetwork management server comprising: a processor; a memory; a dividingmechanism coupled to the processor, the dividing mechanism to divide amesh network into a plurality of logical cells; a placing mechanismcoupled to the processor, the placing mechanism to place a mesh routerin each logical cell; a receiving mechanism coupled to the processor,the receiving mechanism to receive a channel assignment request from arespective mesh router responsive to the mesh router finding anotherneighboring mesh router that has a gateway to the network managementserver; a determining mechanism coupled to the processor, thedetermining mechanism to determine a channel assignment for therespective mesh router based on a set of predetermined rules and networktopology in response to the received channel assignment request; and asending mechanism coupled to the processor, the sending mechanism tosend the channel assignment to the respective mesh router.
 15. Thenetwork management server of claim 14, wherein the set of predeterminedrules comprises: assigning a first channel associated with a firstbackhaul radio antenna of the respective mesh router in a logical cell,a second channel associated with a second backhaul radio antenna and athird channel associated with a third backhaul radio antenna where eachof the first channel, second channel and the third channel are differentfrom one another; and reassigning the first channel in another logicalcell that is (1) approximately opposite to the direction correspondingto a sectored directional antenna of the first backhaul radio antenna,and (2) non-adjacent to the logical cell least three neighboring cells.16. The network management server of claim 14, wherein the mesh routerfinds another neighboring mesh router that has a gateway to the networkmanagement server through a default channel.
 17. The network managementserver of claim 14, wherein, responsive to the mesh router not findinganother neighboring mesh router that has a gateway to the networkmanagement server through a default channel, the mesh router scanschannels to find the other neighboring mesh router that has the gatewayto the network management server.
 18. The network management server ofclaim 14, wherein the respective mesh router is placed during anincremental deployment.
 19. The method of claim 1, wherein thereassigning of the separate channel in another cell creates a buffer ofapproximately two cells in width between directional antennas radiatingthe same channel.
 20. The network device of claim 1, wherein theassigning mechanism reassigns the separate channel in another cell thatcreates a buffer of approximately two cells in width between directionalantennas radiating the same channel.